Eric_Oz_S2

Since stiffening up the front and rear suspension and lowering all round, I am now getting significant front lock up under braking. The S2 has a 18/5 proportioning valve installed on the master cylinder. I have heard that 33/5 is a useful upgrade. I presume with the 33 the pressure reduction will not occur in the rear circuit until 33 bar rather than 18.

Would a 33/5 be "too much" for an S2. The S2 uses the same brakes as the turbo, but the Turbo S and later turbos have larger front pistons (36/44 vs 36/40).

Note that the car is predominantly for track use.

A variable proportioning valve may be a better bet, but it would then need to be professionally installed.

Oddjob

The 33bar valve should be ok on the S2 with stock brakes.

A lot of variables need to be considered (pads, tires, ride height, suspension setup, alignment, driving style, etc), so cant answer with certainty. But I have successfully used the 33bar valve on cars with the small brembos on the front.

I am fairly certain that the next available valve (45bar) is too much for the stock brake setup.

HJK

if its mainly track, go variable, helps a good bit in the wet since the rear is underbraking in the wet.
here's how it looks, but if you don't want to re-route complete lines I think you can put it under bonnet.
H

Dubai944

The 5/33 works well.

por944s2

HKJ, are you still running ABS? If so, how did you route the lines to from ABS unit to valve in cockpit?

Lemming

You can tap into the brake line going from the ABS to the rear of the car under the car. Then just drill two holes through the body, one for the line going to the valve and the other going back to the line under the car.

racerxrick

I have heard that a popular swap is the 928 proportioning valve..anyone have details on the bias with that valve?

racerxrick

oops...I think I just answered it with a search. Looks like the 928 is a 33/5.

I know the previous owner did that to mine as he tracked it a lot more.